Funding sources: this study was supported by Grants-in-Aid for the Scientific Research and Strategic Research Basis Formation Supporting Project from the Ministry of Education, Culture, Sports, Science and Technology of Japan, and by Health and Labour Sciences Research Grants and grants for Research on Measures for Intractable Diseases from the Ministry of Health, Labour and Welfare of Japan. The study was also supported by grants from the Uehara Memorial Foundation, Nakatomi Foundation, Kaibara Morikazu Medical Science Promotion Foundation, Japan Lydia O’Leary Memorial Foundation, Cosmetology Research Foundation, Japanese Dermatological Association (Shiseido Award), Fukuoka Foundation for Sound Health, and Galderma K.K. (Galderma Award).